Originally Posted by Broz
John, I have been a long time learning this but if you had some WW brass I would try it. I know the RWS is great brass and strong as heck but I feel it costs some velocity from the lower case volume. I would almost bet you will be closer to 77 gr + in WW brass. That will get you closer to 2950+. Now that said we all know we need to work up to max when we change component. I understand if you have just bought the RWS but this is the reason I am pulling away from it , velocity. I am not blaming the flyer on the brass, but just think a little more case space could help.. maybe?
So if you could get your hands on just a few pcs of WW to test it might be worth it.
Other than that a primer change to either a FED210 or if ultra cold sub zero temps are in the plan a CCI 250. Sometimes a primer change will bring it all together.
The smaller case capacity will INCREASE pressure, gaining velocity with lower powder charges. You will see max pressure earlier, so be wary of this. I got caught out with Nosler brass due to less capacity than Rem or Win brass. Velocity was identical at 2grs' s less than either of the other brands.
Without a chrony, doping off shooting rocks is not going to be as accurate, the BC is not constant in all velocity ranges, and you may be off quite a ways from the actual dope.
I have never seen a 300WinMag work well with standard primers and slow powders. I have had my best results with either WLRM or Fed215 primers.